BACKGROUND: Sexual dysfunction may significantly affect quality of life and marital relations in the postmenopausal period. The aim of the study was to assess the effect of tibolone on climacteric symptoms and sexuality in late postmenopausal but still symptomatic women. PATIENTS AND METHODS: A six-month prospective study was conducted of two groups of clinically healthy postmenopausal women: a control group (n = 18; mean age 57.8 +/- 4.1 yrs; menopause at 49.7 +/- 2.5; years of amenorrhea 8.1 +/- 4.0 yrs) and a tibolone group (n = 22; mean age 57 +/- 4.5 yrs; menopause at 47.7 +/- 3.9; years of amenorrhea 9.2 +/- 4.6 yrs), who received 2.5 mg tibolone daily for six months. The Kupperman menopausal index (KI) was calculated for both groups at baseline and at six months. Sexual function was assessed by the Female Sexual Function Index (FSFI) questionnaire at the beginning and at the end of the study. The FSFI comprised five main domains: desire, arousal, lubrication, orgasm and pain. Satisfaction and a total score were also recorded. RESULTS: The results showed that during the observation period KI decreased significantly in the tibolone group (15.7 +/- 9.2 vs 11.3 +/- 6.8, p < 0.001), while in the control group no difference was observed. There was a significant improvement of sexual function in the tibolone group in all domains: desire -- from 2.6 +/- 1.0 to 3.1 +/- 1.0 (p < 0.001); arousal -- from 2.3 +/- 1.8 to 3.4 +/- 1.1 (p < 0.001); lubrication - 2.6 +/- 2.1 and 3.5 +/- 1.4 (p < 0.05). The ability to reach orgasm increased (p < 0.001) and pain and discomfort during and after sexual intercourse significantly decreased (p < 0.01). The overall satisfaction and the total score in the treated group changed favourably in a statistically significant manner, while these parameters did not change in the control group. CONCLUSIONS: Treatment with tibolone had a beneficial effect on the climacteric symptoms and sexual function of late postmenopausal women. Moreover, tibolone seems to have an advantage over conventional hormone replacement therapy (HRT) in improving desire and arousal.